References of "Hutsemekers, Damien"
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See detailTRAPPIST: a robotic telescope dedicated to the study of planetary systems
Gillon, Michaël ULg; Jehin, Emmanuel ULg; Magain, Pierre ULg et al

in EPJ Web of Conferences (2011, February 01), 11

We present here a new robotic telescope called TRAPPIST<xref ref-type="fn" rid="FN2">1</xref> (TRAnsiting Planets and PlanetesImals Small Telescope). Equipped with a high-quality CCD camera mounted on a 0 ... [more ▼]

We present here a new robotic telescope called TRAPPIST<xref ref-type="fn" rid="FN2">1</xref> (TRAnsiting Planets and PlanetesImals Small Telescope). Equipped with a high-quality CCD camera mounted on a 0.6 meter light weight optical tube, TRAPPIST has been installed in April 2010 at the ESO La Silla Observatory (Chile), and is now beginning its scientific program. The science goal of TRAPPIST is the study of planetary systems through two approaches: the detection and study of exoplanets, and the study of comets. We describe here the objectives of the project, the hardware, and we present some of the first results obtained during the commissioning phase. [less ▲]

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See detailMESS (Mass-loss of Evolved StarS), a Herschel Key Program
Groenewegen, M. A. T.; Waelkens, C.; Barlow, M. J. et al

in Astronomy and Astrophysics (2011), 526

MESS (Mass-loss of Evolved StarS) is a Guaranteed Time Key Program that uses the PACS and SPIRE instruments on board the Herschel Space Observatory to observe a representative sample of evolved stars ... [more ▼]

MESS (Mass-loss of Evolved StarS) is a Guaranteed Time Key Program that uses the PACS and SPIRE instruments on board the Herschel Space Observatory to observe a representative sample of evolved stars, that include asymptotic giant branch (AGB) and post-AGB stars, planetary nebulae and red supergiants, as well as luminous blue variables, Wolf-Rayet stars and supernova remnants. In total, of order 150 objects are observed in imaging and about 50 objects in spectroscopy. This paper describes the target selection and target list, and the observing strategy. Key science projects are described, and illustrated using results obtained during Herschel's science demonstration phase. Aperture photometry is given for the 70 AGB and post-AGB stars observed up to October 17, 2010, which constitutes the largest single uniform database of far-IR and sub-mm fluxes for late-type stars. [less ▲]

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See detail(596) Scheila
Jehin, Emmanuel ULg; Manfroid, Jean ULg; Hutsemekers, Damien ULg et al

in Central Bureau Electronic Telegrams (CBETs) (2011), 2632

E. Jehin, J. Manfroid, D. Hutsemekers, M. Gillon, and P. Magain, Fonds National de la Recherche Scientifique, Liege University, report on broad- and narrow-band imaging of the (596) Scheila outburst (CBET ... [more ▼]

E. Jehin, J. Manfroid, D. Hutsemekers, M. Gillon, and P. Magain, Fonds National de la Recherche Scientifique, Liege University, report on broad- and narrow-band imaging of the (596) Scheila outburst (CBET 2583) with the TRAPPIST 0.60-m telescope at La Silla, and on optical spectroscopy with the European Southern Observatory's Very Large Telescope (VLT) at Paranal. R-band imaging from 2010 Dec. 12.3 to 21.3 UT revealed two arc-like coma features expanding at a regular pace. The first such feature was 1' long on 2010 Dec. 12, oriented to the northeast and bending to p.a. 280 deg (the anti-solar direction). The second feature was shorter, 30" on Dec. 12, oriented to the south and bending to p.a. 230 deg. Both features were getting larger and fainter with time (4' and 2' long, respectively, on Dec. 21.3). A narrow 45"-long tail, opposite the sun (p.a. 280 deg), was also observed in good seeing. R-band images taken on 2011 Jan. 4.3 and 5.3 after the full moon allowed Jehin et al. to again observe these features, seen as 7' and 4' long, respectively -- and much fainter. This discards any sustained activity of the minor planet. Narrow-band images obtained on 2010 Dec. 12.3 with cometary filters do not show any contribution from gases. A 20-min optical spectrum was obtained with FORS2 at the VLT on Dec. 13.3; it does not show any extended cometary gaseous emissions, but only a spatially extended continuum due to dust-scattered sunlight. Short B, V, R, and I exposures performed nearly every two nights from 2010 Dec. 12.3 to 2011 Jan. 5.3 give a magnitude for the nuclear condensation of V = 14.2 +/- 0.1 over the whole period, in agreement with the "APmag" value reported in the Jet Propulsion Laboratory ephemeris. No flux variation of the nuclear condensation was observed. Those preliminary results are in favor of a collisional scenario to explain the outburst of (596) Scheila, rather than a cometary driven activity. This case might be similar to the outburst of comet P/2010 A2, which may have resulted from an impact of a minor planet (Snodgrass 2010, Nature 467, 814). [less ▲]

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See detailHerschel-PACS observations of Nebulae Ejected by Massive Stars
Vamvatira Nakou, Chloi ULg; Royer, Pierre; Hutsemekers, Damien ULg et al

in Bulletin de la Société Royale des Sciences de Liège (2011), 80

The study of the nebulae ejected from Luminous Blue Variables and the circumstellar bubbles around Wolf-Rayet stars, which radiate strongly in the infrared due to the heating of dust, is crucial for the ... [more ▼]

The study of the nebulae ejected from Luminous Blue Variables and the circumstellar bubbles around Wolf-Rayet stars, which radiate strongly in the infrared due to the heating of dust, is crucial for the understanding of the massive stars evolution. With Herschel we are able to observe these objects in the far-infrared region. In the context of the Mass-loss from Evolved StarS guaranteed time key program, we obtained imaging and spectroscopic observations of nebulae associated with Luminous Blue Variable and Wolf-Rayet stars using PACS, one of the three instruments on-board Herschel. A description of these observations, data analysis and preliminary results are presented. [less ▲]

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See detailStudy of the forbidden oxygen lines in a dozen comets observed at the VLT (ESO)
Decock, Alice ULg; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

in EPSC Abstracts 2011 (2011)

The forbidden lines are difficult to analyse because their detection requires high spectral and spatial resolutions. Their analysis is however interesting because it allows the determination of the ... [more ▼]

The forbidden lines are difficult to analyse because their detection requires high spectral and spatial resolutions. Their analysis is however interesting because it allows the determination of the spatial distribution and the production rate of the parent molecules, supposedly H2O which doesn't have any feature in the optical range. But as shown by Cochran [2] [3], some issues remain about the nature of the parents of the oxygen atoms. Moreover the width of the green line was found larger than that of the red lines. One of the goals of this study is to determine the parent species that photo-dissociate to produce oxygen atoms and see how this process depends on the heliocentric distance. We present here the results of the analysis of a homogeneous set of high quality spectra of 13 different comets observed with UVES at the ESO VLT since 2002 [4] [5]. [less ▲]

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See detailHerschel PACS and SPIRE Observations of comet 103P/Hartley 2
Bockelee-Morvan, D.; Swinyard, B.; Vandenbussche, B. et al

in EPSC Abstracts 2011 (2011)

The ESA Herschel Space Observatory [8] used its full complement of state-of-the-art instruments to observe the far-infrared and submillimetre spectrum and to image the thermal dust radiation of the ... [more ▼]

The ESA Herschel Space Observatory [8] used its full complement of state-of-the-art instruments to observe the far-infrared and submillimetre spectrum and to image the thermal dust radiation of the Jupiter family comet 103P/Hartley 2 in the 70-672 μm spectral range. The observations were carried out in the period 24 October to 17 November 2010, as part of the Herschel Guaranteed Time Key program "Water and related chemistry in the Solar System" (HssO) [6]. We present here observations of H2O lines and of the dust coma made with the Photodetector Array and Camera (PACS) [9] and the Spectral and Photometric Imaging Receiver (SPIRE) [5]. [less ▲]

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See detailObservations of the rotational lines of OH in comets with the Herschel Space Observatory
Crovisier, J.; Bockelée-Morvan, D.; Biver, N. et al

in EPSC Abstracts 2011 (2011)

We present here a search for the OH rotational lines in these spectral scans. In comet 103P/Hartley 2, the 2 3/2(5/2)-2 3/2(3/2) lines at 119 μm and 2 1/2(5/2)-2 1/2(3/2) lines at 99 μm are detected ... [more ▼]

We present here a search for the OH rotational lines in these spectral scans. In comet 103P/Hartley 2, the 2 3/2(5/2)-2 3/2(3/2) lines at 119 μm and 2 1/2(5/2)-2 1/2(3/2) lines at 99 μm are detected. Other lines may be marginally present. Two mechanisms concur to the emission of the OH rotational lines: fluorescence due to solar excitation of the electronic states of OH [8] and prompt emission following the photodissociation of water, which produces the OH radical in electronic, vibrational and rotational excited states [9, 10]. We will compare the observed line intensities with those expected from these mechanisms, using the comet water productions determined from Herschel [6, 7], in order to better constrain the excitation of cometary OH. [less ▲]

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See detailA Multi-wavelength study with the ESO VLT of comet 103P/Hartley2 at the time of the EPOXI encounter
Jehin, Emmanuel ULg; Hutsemekers, Damien ULg; Manfroid, Jean ULg et al

in EPSC Abstracts 2011 (2011)

We report on simultaneous optical and infrared spectroscopic observations of the Jupiter Family comet 103P/Hartley2 performed with the UT-1 and UT-2 8-m Unit Telescopes of the ESO Very Large Telescope ... [more ▼]

We report on simultaneous optical and infrared spectroscopic observations of the Jupiter Family comet 103P/Hartley2 performed with the UT-1 and UT-2 8-m Unit Telescopes of the ESO Very Large Telescope (VLT). These coordinated observations were carried on during several nights (2010 Nov. 5, 9, 10 and 11 UT) around the NASA EPOXI encounter with the comet on Nov. 4 [1] and in support to the key program « Water and related chemistry in the Solar System » (HssO) [2] of the Herschel Space Observatory. From high resolution optical spectroscopy of the CN (0,0) 388 nm band using UVES at UT2 we determined the isotopic ratios 12C/13C = 95 ± 15 and 14N/15N = 155 ± 25 in the CN radical. From the NH2 (0,9,0) and the H2O+ bands around 600 nm, we derived a nuclear spin temperature of 33 ± 3 K for NH3 and 36 +7/-6 K for H2O. These values are similar to those found in Oort- Cloud and Jupiter Family comets. From lowresolution long-slit spectroscopy with FORS2 at UT1 we will determine the CN, C2 and C3 spatial profiles and their production rates. From the high-resolution near-IR spectra that we collected with CRIRES at UT1 we will measure simultaneously the production rates and mixing ratios of the parent molecules H2O, HCN, C2H6, and CH3OH that are well detected in our spectra and we will study the link to the daughter species. [less ▲]

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See detail12C2/12C13C isotopic ratio in comets C/2001 Q4(NEAT) and C/2002 T7 (LINEAR)
Rousselot, P.; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

in EPSC Abstracts 2011 (2011)

The measurement of the carbon isotope abundances ratio in comets allows to constrain the conditions in the outer protosolar nebula. Different measurements of the 12C/13C ratio, using various molecules ... [more ▼]

The measurement of the carbon isotope abundances ratio in comets allows to constrain the conditions in the outer protosolar nebula. Different measurements of the 12C/13C ratio, using various molecules, have already been published for different solar system objects, such as the Sun, the Earth, the Moon, asteroids, planets or comets. So far all these measurements are consistent with 12C/13C' 90 but some significant differences have been seen. In comets this ratio is remarquably constant and equal to 91.0±3.6 [3] for studies based on CN radical but present larger variations with studies based on other radicals [1][5]. In this work we present a new analysis of this ratio, based on two different approachs for modeling the 12C2 and 12C13C emission spectrum and the (1,0) and (2,1) bandheads of 12C13C. Observational data obtained at high resolution (' 70, 000) using the 8.2-m Kueyen telescope (UT2) of the Very Large Telescope (VLT) with the Ultraviolet and Visual Echelle Spectrograph (UVES) instrument have been used to test our modeling and measure the 12C/13C ratio in two different comets: C/2001 Q4(NEAT) and C/2002 T7 (LINEAR). Our modeling and numerical results will be presented. [less ▲]

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See detailLong term photometric monitoring of comet 103P/Hartley2 with the new robotic TRAPPIST telescope
Jehin, Emmanuel ULg; Manfroid, Jean ULg; Hutsemekers, Damien ULg et al

in EPSC Abstracts 2011 (2011)

We report on a long term monitoring of comet 103P/Hartley2 with six cometary narrow band filters using the TRAPPIST 0.60m telescope installed recently at the ESO La Silla observatory in Chile. This new ... [more ▼]

We report on a long term monitoring of comet 103P/Hartley2 with six cometary narrow band filters using the TRAPPIST 0.60m telescope installed recently at the ESO La Silla observatory in Chile. This new robotic telescope is dedicated to exoplanet and solar system research. The comet was observed with the cometary filters during 4 months, from Oct. 29 to Feb. 22. Since then the monitoring continues but only through the BVRI filters and about two times per week. Those observations allowed us to make a detailed light curve of the comet after its perihelion passage and derive production rates of the 4 main species (OH, CN, C2, C3) as well as the dust production rate (Afρ) over that period. The high sampling of our monitoring allowed us to find a periodicity in the gaseous light curves and to deduce a rotation period of 18.4h early November, slowing down to about 19h by the end of December. [less ▲]

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See detailThe Herschel view of nebulae around evolved massive stars
Vamvatira Nakou, Chloi ULg; Royer, P.; Hutsemekers, Damien ULg et al

Conference (2011)

The detailed study of the nebulae ejected from Luminous Blue Variables and the circumstellar bubbles around Wolf-Rayet stars, which radiate strongly in the IR due to the heating of dust, is crucial for ... [more ▼]

The detailed study of the nebulae ejected from Luminous Blue Variables and the circumstellar bubbles around Wolf-Rayet stars, which radiate strongly in the IR due to the heating of dust, is crucial for understanding the massive stars evolution. With Herschel, the largest telescope ever flown in space, we are able to study the gas and the dust in these circumstellar environments in the full far-infrared waveband. In the context of 'Mass-loss of Evolved StarS' Herschel guaranteed time key programme, we have obtained imaging and spectroscopic observations of nebulae associated with Luminous Blue Variable and Wolf-Rayet stars using PACS, one of the three instruments onboard Herschel. A description of these observations and first results of the data analysis are presented. [less ▲]

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See detailResults from the Herschel Key Program MESS
Groenewegen, M. A. T.; Waelkens, C.; Barlow, M. J. et al

in Kerschbaum, F.; Lebzelter, T.; Wing, R. F. (Eds.) Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants. ASPC 445 (2011)

MESS (Mass loss of Evolved StarS) is a Herschel Guaranteed Time Key Program that will image about 100, and do spectroscopy of about 50, post-main-sequence objects of all flavours: AGB stars, post-AGB ... [more ▼]

MESS (Mass loss of Evolved StarS) is a Herschel Guaranteed Time Key Program that will image about 100, and do spectroscopy of about 50, post-main-sequence objects of all flavours: AGB stars, post-AGB stars, planetary nebulae, luminous blue variables, Wolf-Rayet stars, and supernova remnants. In this review the implementation and current status of MESS is outlined, and first results are presented. [less ▲]

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See detailComet 103P/Hartley
Jehin, Emmanuel ULg; Manfroid, Jean ULg; Hutsemekers, Damien ULg et al

in Central Bureau Electronic Telegrams (CBETs) (2010), 2589

CBET 2589 available at Central Bureau for Astronomical Telegrams.

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See detailOccultation by (136199) Eris
Jehin, Emmanuel ULg; Manfroid, Jean ULg; Gillon, Michaël ULg et al

in International Astronomical Union Circulars [=IAUCs] (2010), 9184

E. Jehin, J. Manfroid, M. Gillon, D. Hutsemekers, and P. Magain report that they observed an occultation of a star of magnitude I about 15.2 by the dwarf planet Eris (then at V about 18.7) on Nov. 6 using ... [more ▼]

E. Jehin, J. Manfroid, M. Gillon, D. Hutsemekers, and P. Magain report that they observed an occultation of a star of magnitude I about 15.2 by the dwarf planet Eris (then at V about 18.7) on Nov. 6 using the new telescope TRAPPIST at the European Southern Observatory (La Silla). A series of 3-s exposures of a field of size 3' x 3' (1".3/pixel) were secured in fast-readout mode (with a deadtime of 1.5 s), starting at 01h50m UT for one hour. Seven frames centered at 02h19m34s UT allowed them to derive the start of the occultation as 02h19m16s.75 +/- 0s.75 and the end as 02h19m47s.6 +/- 0s.2, for a total occultation time of 30.4 +/- 1.0 seconds. The predictions (see above) made by the Rio de Janeiro group (Assafin et al., Nov. 5) and by J. L. Ortiz estimated the time of the occultation around 02h18m UT for Chile, in good agreement with the observations. During the occultation, a point source is detected with a magnitude corresponding to that of Eris. A small flux increase was also seen at the middle of the occultation, which might result from refraction in Eris' atmosphere (Elliot and Olkin 1996, Ann. Rev. Earth Planet. Sci. 24, 89). Eris is by far the most-remote solar-system object observed to date via stellar occultation, with a geocentric distance of about 96 AU. TRAPPIST is a project driven by the University of Liege, in close collaboration with the Observatory of Geneva, supported by the Belgian Fund for Scientific Research and the Swiss National Science Foundation. [less ▲]

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See detailWater production in comet 81P/Wild 2 as determined by Herschel/HIFI
de Val-Borro, M.; Hartogh, P.; Crovisier, J. et al

in Astronomy and Astrophysics (2010), 521(Letters), 501-5

The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations of water production rates in comets. In this Letter we ... [more ▼]

The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations of water production rates in comets. In this Letter we present HIFI observations of the fundamental 1[SUB]10[/SUB]-1[SUB]01[/SUB] (557 GHz) ortho and 1[SUB]11[/SUB]-[SUB]00[/SUB] (1113 GHz) para rotational transitions of water in comet 81P/Wild 2 acquired in February 2010. We mapped the extent of the water line emission with five point scans. Line profiles are computed using excitation models which include excitation by collisions with electrons and neutrals and solar infrared radiation. We derive a mean water production rate of 1.0 × 10[SUP]28[/SUP] molecules s[SUP]-1[/SUP] at a heliocentric distance of 1.61 AU about 20 days before perihelion, in agreement with production rates measured from the ground using observations of the 18-cm OH lines. Furthermore, we constrain the electron density profile and gas kinetic temperature, and estimate the coma expansion velocity by fitting the water line shapes. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Figure 5 (page 5) is only available in electronic form at <A href="http://www.aanda.org">http://www.aanda.org</A> [less ▲]

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See detailThe 3/4 July 2010 Pluto Stellar-Occultation Observations
Pasachoff, Jay M; Elliot, J. L.; Souza, S. P. et al

in Bulletin of the American Astronomical Society (2010, October 01), 42

Continuing our monitoring of Pluto's atmospheric temperature and pressure, previously shown by us to be increasing (Elliot et al., Nature 424, 165, 2003; Pasachoff et al., AJ 129, 1718, 2005) and ... [more ▼]

Continuing our monitoring of Pluto's atmospheric temperature and pressure, previously shown by us to be increasing (Elliot et al., Nature 424, 165, 2003; Pasachoff et al., AJ 129, 1718, 2005) and subsequently found by us to be leveling off (Elliot et al., AJ 134, 1, 2007), we report on a stellar occultation by Pluto of UCAC2 mag=15.3, observed from South America and Africa on 4 July 2010 UT. Success was achieved with a 0.45 m at Cerro Calan using one of our POETS (Portable Occultation, Eclipse, and Transit System; Souza et al. PASP 118, 1550, 2006), a 1.0 SMARTS (Small and Medium Aperture Research Telescope System) at Cerro Tololo, four 0.6 m telescopes of PROMPT (Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes) on Cerro Tololo, and TRAPPIST's (TRansiting Planets and Planetesimals Small Telescope) 0.6-m telescope on La Silla in Chile; the 0.35 m telescope of U. Ponta Grossa, Brazil; and the 0.75-m ATOM (Automatic Telescope for Optical Monitoring), Namibia, using POETS. Winds prevented opening the 6.5 m Magellan/Clay telescope on Las Campanas, Chile, with its own frame-transfer camera, and clouds obscured the 1.9 m telescope at Sutherland, South Africa, which had POETS. With shadow velocity 23.6 km/s, it was a rapid event: maximum occultation <2 minutes. The observations were supported in part by grants NNX08AO50G to Williams College and NNX10AB27G to MIT from NASA's Planetary Astronomy Division, and NNH08AI17I to USNO for astrometry. Student participation was supported in part by NASA's Massachusetts Space Grant and NSF's REU. Japan's government donated U. Chile's Cerro Calan Goto telescope. PROMPT observations were made possible by the Robert Martin Ayers Science Fund. TRAPPIST is a project driven by the University of Liège, in close collaboration with the Observatory of Geneva, supported by the Belgian Fund for Scientific Research and the Swiss National Science Foundation. [less ▲]

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See detailOPRs of Ammonia versus 14N/15N Ratios in CN in 15 Comets
Shinnaka, Yoshiharu; Kawakita, H.; Kobayashi, H. et al

in Bulletin of the American Astronomical Society (2010, October 01), 42

The solar system was formed from interstellar matter 4.6 Gyrs ago and comets are considered as remnants of icy planetesimals formed in the early solar system. One of interesting primordial characters of ... [more ▼]

The solar system was formed from interstellar matter 4.6 Gyrs ago and comets are considered as remnants of icy planetesimals formed in the early solar system. One of interesting primordial characters of cometary ice is an ortho-to-para abundance ratio (OPR) of molecules such as H2O, NH3, etc. The OPR probably indicates the molecular formation temperatures in the solar nebula or in the pre-solar molecular cloud. We determined the OPRs of ammonia by using the high dispersion optical spectra of NH2 in 15 comets: C/1995 O1 (Hale-Bopp), C/1999 S4 (LINEAR), C/2001 A2 (LINEAR), C/2000 WM1 (LINEAR), 153P/Ikeya-Zhang, C/2002 V1 (NEAT), C/2002 X5 (Kudo-Fujikawa), C/2002 Y1 (Juels-Holvorcem), C/2001 Q4 (NEAT), C/2002 T7 (LINEAR), C/2003 K4 (LINEAR), 8P/Tuttle, 88P/Howell, 9P/Tempel 1, and 73P-B and -C/Schwassmann-Wachmann 3. The observations were mainly carried out by the Ultraviolet and Visual Echelle Spectrograph (UVES) mounted on the Very Large Telescope (VLT) in Chile. Other telescopes/instruments were also used in some cases. The OPRs of ammonia are determined from OPRs of NH2 (0,9,0) ro-vibronic band around 600 nm. Although absorption lines (by the telluric atmosphere) and cometary C2 emission lines blended affected to NH2 emission lines in this region, we removed them in our analysis. The determined OPRs of ammonia clustered around 30K but not in the cases of 73P-B and -C. This situation is very similar to that of 14N/15N ratios in CN (i.e., 73P-B and -C are quite peculiar relative to other comets). We discuss about the relationship between the OPRs of ammonia and 14N/15N ratios in CN in these 15 comets. Our results indicate the formation of materials at relatively higher temperatures for 73P-B and -C than other comets. [less ▲]

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See detailComet 29P/Schwassmann-Wachmann Observed with the Herschel Space Observatory: Detection of Water Vapour and Dust Far-IR Thermal Emission
Bockelee-Morvan, Dominique; Biver, N.; Crovisier, J. et al

in Bulletin of the American Astronomical Society (2010, October 01), 42

The distant comet 29P/Schwassmann-Wachmann was observed with the HIFI, PACS and SPIRE instruments aboard the Herschel Space Observatory, as part of the guaranteed time key programme "Water and related ... [more ▼]

The distant comet 29P/Schwassmann-Wachmann was observed with the HIFI, PACS and SPIRE instruments aboard the Herschel Space Observatory, as part of the guaranteed time key programme "Water and related chemistry in the Solar System" (KP-GT HssO). Supporting observations of the 230 GHz CO line were carried out with the IRAM 30-m telescope. The HIFI observations of the 557 GHz H2O line were performed on 19.05 April 2010, about 2 days after a major outburst, and on 11.02 May 2010, when 29P was in a more quiescent phase. H2O was detected on both dates with a production rate corresponding to about 1/10th the CO production, assuming near-nucleus production. The H2O line shape is consistent with release of water vapour from icy grains. PACS and SPIRE imaging data from 70 to 500 micrometers were acquired mid-June 2010 when the comet was in a quiescent phase. The continuum emission detected in the 70-μm and 160-μm PACS images is weakly extended with respect to the PSF, suggesting a major contribution from the nucleus or from slowly moving large grains. [less ▲]

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See detailOptical circular polarization in quasars
Hutsemekers, Damien ULg; Borguet, Benoît ULg; Sluse, D. et al

in Astronomy and Astrophysics (2010), 520(Letters), 71-5

We present new optical circular polarization measurements with typical uncertainties <0.1% for a sample of 21 quasars. All but two objects have null circular polarization. We use this result to constrain ... [more ▼]

We present new optical circular polarization measurements with typical uncertainties <0.1% for a sample of 21 quasars. All but two objects have null circular polarization. We use this result to constrain the polarization due to photon-pseudoscalar mixing along the line of sight. We detect significant (> 3σ) circular polarization in two blazars with high linear polarization and discuss the implications of this result for quasar physics. In particular, the recorded polarization degrees may be indicative of magnetic fields as strong as 1 kG or a significant contribution of inverse Compton scattering to the optical continuum. Based on observations made with ESO Telescopes at the La Silla Observatory (Chile). ESO program ID: 79.A-0625(B).Appendices are only available in electronic form at <A href="http://www.aanda.org">http://www.aanda.org</A> [less ▲]

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See detailMicrolensing in H1413+117: disentangling line profile emission and absorption in a broad absorption line quasar
Hutsemekers, Damien ULg; Borguet, Benoît ULg; Sluse, D. et al

in Astronomy and Astrophysics (2010), 519

On the basis of 16 years of spectroscopic observations of the four components of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to visible rest-frame ... [more ▼]

On the basis of 16 years of spectroscopic observations of the four components of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to visible rest-frame spectral range, we analyze the spectral differences observed in the P Cygni-type line profiles and have used the microlensing effect to derive new clues to the BAL profile formation. We first find that the absorption gradually decreases with time in all components and that this intrinsic variation is accompanied by a decrease in the intensity of the emission. We confirm that the spectral differences observed in component D can be attributed to a microlensing effect lasting at least a decade. We show that microlensing magnifies the continuum source in image D, leaving the emission line region essentially unaffected. We interpret the differences seen in the absorption profiles of component D as the result of an emission line superimposed onto a nearly black absorption profile. We also find that the continuum source and a part of the broad emission line region are likely de-magnified in component C, while components A and B are not affected by microlensing. Differential dust extinction is measured between the A and B lines of sight. We show that microlensing of the continuum source in component D has a chromatic dependence compatible with the thermal continuum emission of a standard Shakura-Sunyaev accretion disk. Using a simple decomposition method to separate the part of the line profiles affected by microlensing and coming from a compact region from the part unaffected by this effect and coming from a larger region, we disentangle the true absorption line profiles from the true emission line profiles. The extracted emission line profiles appear double-peaked, suggesting that the emission is occulted by a strong absorber, narrower in velocity than the full absorption profile, and emitting little by itself. We propose that the outflow around H1413+117 is constituted by a high-velocity polar flow and a denser, lower velocity disk seen nearly edge-on. Finally, we report on the first ground-based polarimetric measurements of the four components of H1413+117. Based on observations made with the Canada-France-Hawaii Telescope (Hawaii), with ESO Telescopes at the Paranal Observatory (Chile) and with the NASA/ESA Hubble Space Telescope, and obtained from the data archive at the Space Telescope Institute. ESO program ID: 074.A-0152, 075.B-0675, 081.A-0023. [less ▲]

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